A Mod to allow you to flip the connector on the keyboard/dock half of the
TF, so that you could mount the tablet half with the display facing out.
That way you could get the extra battery time and the other ports, including
the full sized SD reader, yet still use it as a tablet. (Admittedly a heavy one.)

The part that needs to be able to turn is just the actual connector part, not
the whole hinge bracket that the tablet plugs into. (I think the locking
mechanism and the support posts would still work with the tablet in upside
down.) What I'm thinking of would be a mechanical knob that flips the
connector, not a permanent change.

As the bottom connector of the Transformer is the charge port, it would make sense to have two such charge cables connected at the USB 3.0 ends with a dual female connectors then the males ends would act like a tether cable that effectively connects the Transformer to the keyboard dock. A low tech umbilical cord!

It would only need that (mod) tether cable, and perhaps the connector switch on the dock (half)closed to signify a connection is made.

Think of the possibilities, I would just scrap the actual cable and go with a dongle and make it wireless via wifi, BT, IR, ...

As the bottom connector of the Transformer is the charge port, it would make sense to have two such charge cables connected at the USB 3.0 ends with a dual female connectors then the males ends would act like a tether cable that effectively connects the Transformer to the keyboard dock. A low tech umbilical cord!

It would only need that (mod) tether cable, and perhaps the connector switch on the dock (half)closed to signify a connection is made.

Think of the possibilities, I would just scrap the actual cable and go with a dongle and make it wireless via wifi, BT, IR, ...

Now that would be a mod!!!!!!

Hmm... you might get a wireless connection for all the exchanged signals
but I can't picture "Power over Wireless" to take advantage of the extra
battery. Still the cable idea might be neat you could even rig it so the
dock would fit in the pouch for a hydration pack on a utility vest. There
would be easy routing for ear/headphones and the "umbilical".
Perhaps some flexible solar panels to keep the base charged?